Missouri Water Quality Report: 5,602 Water-System Violations Mapped to 850 ZIPs
1,934 water systems · 850 ZIP codes · 5,602 violations
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO
ZipCheckup tracks EPA drinking-water compliance for 1,934 public water systems serving 850 ZIP codes in Missouri. The state record shows 5,602 EPA violations, 469 health-based.
City Water Quality Map: Missouri
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Cities with Most Violations in Missouri
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Shell Knob | 103 | 5 | 3,957 | Details → | |
| 2 | Lampe | 97 | 3 | 1,869 | Details → | |
| 3 | Blue Eye | 93 | 3 | 1,784 | Details → | |
| 4 | Kennett | 92 | 4 | 11,964 | Details → | |
| 5 | Bourbon | 89 | 3 | 5,086 | Details → | |
| 6 | Kansas City | 60 | 20 | 602,147 | Details → | |
| 7 | Marthasville | 57 | 5 | 6,593 | Details → | |
| 8 | High Ridge | 49 | 5 | 17,480 | Details → | |
| 9 | Wappapello | 44 | 5 | 2,183 | Details → | |
| 10 | Senath | 44 | 2 | 2,098 | Details → |
Most Common Contaminants in Missouri
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Lead and Copper Rule Revisions | Treatment Technique | 1,088 | 559 | No |
| Lead and Copper Rule | Treatment Technique | 688 | 423 | No |
| Consumer Confidence Rule | Reporting | 467 | 269 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 442 | 219 | Yes |
| Groundwater Rule | Treatment Technique | 368 | 159 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 312 | 180 | Yes |
| Public Notice Rule | Reporting | 285 | 206 | No |
| Interim Enhanced Surface Water Treatment Rule | Treatment Technique | 97 | 35 | Yes |
| Simazine | Organic | 65 | 34 | No |
| Atrazine | Organic | 65 | 34 | No |
Water Quality Overview
Missouri has 1,934 community water systems represented across 850 directly mapped ZIP records. The associated city records cover approximately 7,206,479 people. The available records contain 5,602 EPA violations, including 469 health-based violations.
Health-based violations account for 8% of all violations in Missouri. These violations indicate contaminant levels that may pose direct risks to human health, as opposed to monitoring or reporting failures.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 469 | 8.4% |
| Monitoring/Reporting | 5,133 | 91.6% |
| Total | 5,602 | 100% |
Health-based violations are MCL, MRDL (disinfectant) and treatment-technique violations. Monitoring violations indicate failures to test or report - these do not necessarily mean unsafe water, but they mean the water was not properly verified.
Cities with Most Violations
The following cities in Missouri have the highest number of EPA violations:
| Rank | City | Violations | Water Systems | Population |
|---|---|---|---|---|
| 1 | Shell Knob | 103 | 5 | 3,957 |
| 2 | Lampe | 97 | 3 | 1,869 |
| 3 | Blue Eye | 93 | 3 | 1,784 |
| 4 | Kennett | 92 | 4 | 11,964 |
| 5 | Bourbon | 89 | 3 | 5,086 |
| 6 | Kansas City | 60 | 20 | 602,147 |
| 7 | Marthasville | 57 | 5 | 6,593 |
| 8 | High Ridge | 49 | 5 | 17,480 |
| 9 | Wappapello | 44 | 5 | 2,183 |
| 10 | Senath | 44 | 2 | 2,098 |
Violation counts are cumulative across all water systems serving each city. Higher counts may reflect larger systems with more monitoring requirements, not necessarily worse water quality.
Violation Trend Over Time
Year-by-year EPA violations recorded across all water systems in Missouri:
| Year | Health-based violations |
|---|---|
| 2021 | 31 |
| 2022 | 54 |
| 2023 | 63 |
| 2024 | 134 |
| 2025 | 68 |
| 2026 | 35 |
Health-based violations have increased from 31 in 2021 to 35 in 2026. This trend warrants monitoring and may reflect expanded testing requirements rather than worsening quality.
Most Common Contaminants
The following contaminants have caused the most violations across Missouri water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Lead and Copper Rule Revisions | Treatment Technique | 1,088 | 559 | No |
| Lead and Copper Rule | Treatment Technique | 688 | 423 | No |
| Consumer Confidence Rule | Reporting | 467 | 269 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 442 | 219 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 312 | 180 | Yes |
| Public Notice Rule | Reporting | 285 | 206 | No |
| Interim Enhanced Surface Water Treatment Rule | Treatment Technique | 97 | 35 | Yes |
| Atrazine | Organic | 65 | 34 | No |
| E. coli | Microbiological | 55 | 46 | No |
| Surface Water Treatment Rule | Treatment Technique | 54 | 32 | Yes |
How to Check Your Water in Missouri
Enter your ZIP code on ZipCheckup for detailed water-system data including contaminant levels and violation history; the separate Home Safety Score is a multi-source index
Request your CCR - every water utility must provide an annual Consumer Confidence Report
Get a home test - certified kits ($20-$50) or professional lab tests ($150-$400)
Consider filtration - NSF-certified filters can address specific contaminants found in your area
EPA Enforcement
The EPA and state regulators have taken enforcement actions against water systems in Missouri. Enforcement actions range from compliance assistance to formal orders and penalties.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Updated daily.
What are EPA violations?
Health-based violations are EPA violations of a Maximum Contaminant Level (MCL), a Maximum Residual Disinfectant Level (MRDL) or a required treatment technique - the enforceable standards designed to protect human health. Missouri has 469 such violations across its water systems. Not all violations cause illness; review each violation type and duration to understand possible health implications.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grades summarize ZipCheckup's scoring inputs; review the underlying records for specific issues. Grades are calculated per ZIP code and aggregated at the city, county, and state level.
Wondering about your tap water?
Water quality varies by ZIP code. Enter yours to see contaminant data, violations, and filtration recommendations specific to your area.
Check Your ZIP Code Water Quality →Frequently Asked Questions
Is the tap water safe to drink in Missouri?
Records for 1,934 community water systems mapped to ZIPs in Missouri show 5,602 reported violations, including 469 health-based. Water quality varies by city and ZIP code - check your specific location for detailed results.
How many violations are on record for water systems serving Missouri?
Missouri has 5,602 EPA violations on record across 850 ZIP codes; 469 are classified as health-based violations. The remainder are monitoring or reporting violations.
Which city in Missouri has the worst water quality?
Shell Knob, MO has the most recorded EPA violations (103) among the cities with mapped water systems in Missouri in our data. Check your water supplier's report and test your tap water for the most accurate picture of your local water quality.
Which city in Missouri has the best water quality?
Violation records vary by water system across Missouri. Check individual city reports for details.
What contaminants are found in Missouri drinking water?
EPA regulates over 90 drinking-water contaminants nationally; water systems in Missouri monitor those applicable to each system, which can include lead, copper, nitrate, disinfection byproducts, and bacteria. The most common violations vary by region - check your ZIP code for contaminant-specific data.